DE2064155C3 - Aqueous phenol / formaldehyde resin suspension and its use - Google Patents

Description

contains, in which M is an alkali metal or ammonium, η is an integer from 1 to 9 and Ri and R _{2 are} hydrogen or an alkyl group having 1 to 4 carbon atoms.

2. Aqueous suspension based on a Phenol / formaldehyde resin and a dispersant according to Claim 1, characterized in that that the dispersant in an amount of 3 to 15 % By weight based on the phenol / formaldehyde resin is present.

3. Aqueous suspension based on a phenol / formaldehyde resin and a dispersant according to claim 1, characterized in that that a salt of polyoxyethylene alkyl sulfate or alkyl phenyl sulfate of the general formula

RO- (C ₂ H ₄ O) _n SO ₃ M

where R is an alkyl or alkylphenyl group in which the alkyl group contains 8 to 18 carbon atoms, n 'is an integer of at most 6 and M is an alkali metal and ammonium, is present as an additional dispersant

4. Aqueous suspension based on a phenol / formaldehyde resin and a dispersing agent 45

means according to claim 3, characterized in that the additional dispersant in an amount from 0.1 to 1% by weight based on the phenol / formaldehyde resin

5. Use of the aqueous phenol / formaldehyde resin suspension according to Claim 1 for the production of a pressure-sensitive copier paper.

It is well known that a phenol or a Phenol derivative when reacted with formaldehyde in the presence of an acidic catalyst Phenol / formaldehyde resin has been yielding in recent years have phenol-formaldehyde resins as' materials for pressure sensitive copy paper in addition to theirs Use as molded compounds found interest.

A pressure-sensitive copier material that does not require carbon paper or a so-called "non-carbon paper" was also developed. This material was developed is available in the following form: A copy paper, which consists of a structure that includes an upper sheet of paper Microcapsules attached to the bottom thereof and a lower sheet of paper with an acidic substance, which is attached to the top thereof includes. The microcapsules are covered with a solid protective colloid coated and after a complicated flocculation process from oily drops, which have a basic Containing dye, made The oily droplets are made by adding a non-volatile oil

with a basic dye dissolved in water with the help of a protective colloid such as gum arabic or Gelatin, emulsions. The microcapsules on the paper are destroyed under the pressure, and if the two surfaces to be treated adjoin each other, will

μ the oil, which contains the basic dye, is released

and with the acidic substance on the top surface

of the lower sheet of paper brought into contact so that

a color develops.

Previously considered "acidic substance" as used herein

called acidic clays is used, however these materials lose this required coloring effect at high atmospheric humidity and tend to gradually, over time, themselves

after color was developed to discolor discolor or in, so that this material for permanent documents is inappropriate. To improve this disadvantage, a process has been proposed in which reactive acidic polymers are used (cf. JP-PS 20144/67); various examples of the use of phenol-formaldehyde polymers are given in this process.

Processes known to date for the preparation of phenol-formaldehyde polymers include the one described in Industrial Engineering Chemistry, Vol. 43, pages 134-141, January 1951. A phenol and formaldehyde are reacted in a molar ratio of 1: 0.6-1.0 in the presence of one or more acidic catalysts such as hydrochloric acid, oxalic acid or p-toluenesulfonic acid, the reaction system being reacted at a pH of 1 holds until 2 or lower The mixture is refluxed for a period of time and then water is separated from the reaction mixture; alternatively, the reaction mixture bull atmospheric pressure or, if desired, under reduced pressure at a temperature of 120 to 180 ⁰ C is heated, thereby removing water and unreacted materials. After cooling, the solidified product is comminuted so that a lump-shaped polymer is obtained

A general method of applying such resins to paper is to grind the resin to a fine powder with a powerful grinder, add a dispersing agent, spreading agent or similar additive to the powder to make an aqueous dispersion, and then pour it onto the powder Paper applies always to suspensions of such phenol-formaldehyde resins so extremely unstable that sedimentation occurs quickly when the suspension is left to stand. It was therefore necessary to prepare the suspension immediately before use and to stir it continuously. In addition, sedimentation or coagulation often occurs during the application of the suspension, which leads to difficulties in the operation of the suitable devices. As a result, labor-intensive and time-consuming procedures are required to overhaul the apparatus, and productivity is considerably reduced

When a suspension in such an unstable State is applied to paper, the amount applied is often in a non-uniform form, so and the dispersion state of the applied resin particles is different in different areas, so that the inking speed of the copy paper and the resulting color density are unequal and it it is impossible to produce a pressure-sensitive copier paper of good quality.

Accordingly, it is an object of the invention to provide a stable Suspension of a phenol-formaldehyde resin is available to ask, which, if left standing, does not fail or separates out The suspension should continue to avoid coagulation, so that the procedural measures and the Devices that are used to apply the suspension to paper can stabilize. One under Decapitated paper produced using the suspension according to the invention should therefore be of good quality own and the applied amount of resin and the Particle state of the resin should be uniform.

A variety of dispersants are well known and are also used in combination with the substances to be dispersed according to their particular purposes. However, there is no general rule for the selection of such combinations. Accordingly, various dispersants have been developed. From GB-PS 5 23 222 it is known that a phenolsulfonic acid-formaldehyde concentrate is effective as a dispersant for phenol-formaldehyde resins. However, this dispersant is found to be unsuitable for the purpose of the invention

It has now been found that a very stable aqueous phenol / formaldehyde resin suspension can be obtained if an inorganic salt of a condensate is used as the dispersant when dispersing the following phenol / formaldehyde resin in water used by naphthalenesulfonic acids or alkylnaphthalenesulfonic acid with formaldehyde

The invention thus provides an aqueous dispersion based on a phenol / formaldehyde resin and a dispersant, which thereby is characterized in that it is a phenol / formaldehyde resin of the formula

wherein m is an integer from 0 to 10 and Ai, A ₂ and A ₃ each represent an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 5 to 18 carbon atoms, an aryl or aralkyl group having 6 to 18 carbon atoms or a halogen atom, where the molar ratio of formaldehyde to the phenol compound is 0.6 to 1.0: 1.0, and the dispersant is an inorganic salt of a naphthalenesulfonic acid or alkylnaphthalenesulfonic acid / formaldehyde condensate of the general formula

contains, where M is an alkali metal or ammonium, π is an integer from 1 to 9 and Ri and R _{2 are} hydrogen or an alkyl group having 1 to 4 carbon atoms.

In the dispersant, the alkyl groups Ri and R _{2 can be} methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl and tert-butyl groups.

The condensation needed to produce the dispersant

The rend naphthalenesulfanic acid or alkynaplithalinsulfonic acid can be an α-sulfonic or p-sulfonic acid. Suitable alkylnaphthalene-sulfonic acids are; Monoalky | naphthaIin - «- sulfonic acids, wic Z-methylnaphthalene-i-sulfonic acid, 4-methylnaphthalene-t-sulfonic acid, 7-methylnaphthalene-1-sulfonic acid, 4-ethylnaphthalene-l-sulfonic acid, 2-isopropylnaphthalene-i-sulfonic acid, 5-isopropylnaphtbalin-i-sulfonic acid and 6-n-butylnaphthalene-1-sulfonic acid; and Dialylnaphthalene - «- sulfonic acids, such as 2,6-dimethylnaphthalene-1-sulfonic acid, 3,7-dimethyinaphthalene-1-sulfonic acid, 6,7-dimethylnaphthalene-1-sulfonic acid, 4,7-dimethylnaphthalene-1-sulfonic acid, 4,6-di-n-butylnaphthalene-1-sulfonic acid, 2,6-di-tert-butylnaphthalene-1-sulfonic acid and 3,7-di-tert-butylnaphthalene-1-sulfonic acid. Suitable alkylnaphthalene-ß-sulfonic acids are: Monoalkylnaphthalene - /? - sulfonic acids, such as 1-methylnaphthalene-2-sulfonic acid, 4-methylnaphthalene-2-sulfonic acid, e-methylnaphthalene-sulfonic acid, e-methylnaphthalene ^ -sulfonic acid, ö-isopropylnaphthalene ^ -sulfonic acid, 1-n-butylnaphthalene-2-sulfonic acid and 7-tert-butylnaphthalene-2-sulfonic acid; and dialkylnaphthalene - ^ - sulfonic acids, such as a.e-dimethylnaphthalene ^ -sulfonic acid, S ^ -dimethylnaphthalene ^ -sulfonic acid, ej-dimethylnaphthalene ^ -sulfonic acid, 'V-Diisopropylnaphthalene ^ -sulfonic acid ,, 3,8-diisopropylnaphthalene-2-sulfonic acid and ^ -Di-tert-butylnaphthalene ^ -sulfoiic acid. Suitable processes for the preparation of the alkylnaphthalene sulfonic acids and naphthalene sulfonic acids are z. B. in the German patent 10 58 983 described. The dispersant is preferably in a Amount of 3 to 15 wt .-%, based on the formaldehyde resin, used

The stabilization effect can be increased by additionally adding a salt of a polyoxyethylene alkyl sulfate or alkyl phenyl sulfate of the general formula as a further dispersant

RO- (C ₂ H ₄ O) _n -SO ₃ M

used, in which R is an alkyl or alkylphenyl group in which the alkyl group contains 8 to 18 carbon atoms, n 'is an integer of at most 6 and M is an alkylimetal or ammonium. Among these additional dispersants, the following are particularly suitable according to the invention:

Sodium polyoxyethylene stearyl sulfate, Sodium polyoxyethylene dodecyl sulfate, Sodium polyoxyethylene nonylphenyl sulfate etc.

These compounds are preferably in an amount of 0.1 to 1% by weight based on the Phenol-formaldehyde resin, incorporated.

Suitable rhenol / formaldehyde resins present in the phenol / formaldehyde resin suspension according to the invention are prepared by the Formaldehyde component, i.e. formaldehyde, formalin, para-formaldehyde or other formaldehyde-forming Compounds with the phenolic component in a molar ratio of 0.6 to 1.0: 1.0 and in the presence an acidic catalyst.

In the phenol / formaldehyde resin, Ai, Aj and

A3 as alkyl groups with I to 18 carbon atoms in each of its isomeric forms exist. If they mean halogen atoms, they include chlorine, bromine or Fluorine atoms,

The substituted phenols useful in the present invention include the following;

p-cresol, p-ethylphenol, p-sele-butylphenol, p-tert-butylphenol, p-tert-amylphenol, p-tert-hexylphenol, p-isooctylphenol,

p-nonylphenol, p-decylphenol,

p-DodecylphenoLp-Tetradecylphenol, p-octadecylphenol; p -cyclohexylphenol; p-phenylphenol; p-chlorophenol, p-bromophenol. These compounds can be used alone or in mixtures gen as a starting material for the production of the resin be used. Furthermore, a mixture of resins can be used. Especially useful under The para-substituted phenols mentioned above are p-chlorophenol and p-phenylphenol.

An aqueous suspension of the condensate can be prepared by a wet pulverization process, in which in the usual manner he £ dispersants and a colloid mill, a waJzernühie or a Sand grinder can be used. The part Chen size of the phenol-formaldehyde resin in the water gene suspension is 5 μ or less, preferably 1 μ or less. When a resin with a larger Particle size is used, the stability of the suspension and the coloring effect, which is reduced if the condensate is used for a print sensitive copier paper, it deteriorates.

The content of phenol / formaldehyde resin in the aqueous suspension can be freely below about 60 % By weight can be selected. A lower concentration tion is preferred if the suspension is equalized mig wants to apply to paper for a pressure-sensitive copy structure, whereas a higher concentration when transporting the suspension is advantageous The stability of the suspension is not affected, when the suspension is made in high concentration and when used, is diluted with water to a desired concentration. Thus becomes usually made a high concentration suspension

Furthermore, the aqueous according to the invention Suspensions by usual procedures, e.g. B. with Using a spray dryer or a drum dryer. The resulting solid product becomes a fine powder with a particle size

so of less than 0.149 mm or preferably less than 0.105 mm pulverized. The resultant powder is noticeably opposed to the aqueous suspension the processing and the transport are advantageous and can even after long storage by simple Adding water with stirring to the original aqueous suspension can be restored.

If a lumpy phenol / formaldehyde resin obtained by a conventional method is used, the resin must be prepared before the aqueous suspension of dry pulverization treatment using a vigorous crusher be subjected to the device. However, such crushing and pulverizing treatment is disadvantageous because of the spreading of fine dusts during the pulverization of the lumpy resin not only affects jobs, but does so too tends to form an explosive dust. In particular, when the resin is used as a material for making a

pressure-sensitive copying paper is used, greatly affects the pulverization of the resin Measure the desired coloring effect. Although a uniform distribution of particle size is highest is important, regulation of the pulverization process is very difficult.

Therefore, it is preferred to dissolve the phenol / formaldehyde resin in aqueous alkali, add an acid to the aqueous solution to form a precipitate, the precipitate is filtered so that a moist in Filter cake obtained that is used. An aqueous suspension with particularly good properties is obtained one also, if one considers the resin formation by condensation of phenol and formaldehyde in the presence an acidic catalyst and an organic r> solvent carried out, one aqueous alkali for Adding solution of the resin formed, separating the organic solvent from the aqueous solution, under vigorous stirring with formation of a precipitate acid is added, the precipitate is separated off and the -> <> resulting wet filter cake of the phenol / formaldehyde resin is used. In this condensation reaction the molar ratio of phenol to formaldehyde is 0.6 to 1.0: 1.0, and benzene, toluene, xylene, Pentane, heptane, hexane. Cyclohexane or trichloroethane _ >> are suitable as organic solvents. The alkali, such as sodium hydroxide, which is used to dissolve the resin, is used in an amount that is sufficient to dissolve the resin, and the amount is generally in the range of 0.3 to 1.0 moles per mole of des to used phenol. In addition, the quality of the product is improved when the concentration of the Resin in the alkaline solution is small, preferably 10% by weight or less.

The precipitation temperature is in the range of room π temperature to 70 ° C, preferably in the range of 15 to 45 ⁰ C. A common inorganic or organic acid, such as hydrochloric acid, sulfuric acid, oxalic acid, acetic acid or phosphoric acid is to neutralize the alkaline solution to a -to pH of 7 or less is used to precipitate the resin out of solution. When the resin is precipitated, it is preferred ^{to stir vigorously at a temperature below 70 °} C. so that the precipitated resin is in amorphous particle form with a diameter of 3 -r to 80 μ. At temperatures below 70 ° C, the growth of the polymer crystal lattice is incomplete, and the resulting resin has a low degree of crystallization, which can be determined by X-ray diffraction measurements, and contains a large proportion in amorphous form, which allows rapid color development of the basic dye, which is thus in Contact is brought about. A thus-obtained wet cake can be easily transferred into an aqueous suspension, without being aiifwendi ge procedures such as drying and crushing, has to perform.

Since the aqueous suspension obtained by this method has excellent stability and the particle size of the resin is small and uniform, the suspension is particularly well suited for Manufacture of pressure sensitive copier paper that is uniform in quality and color is excellent

The invention thus also relates to the use of the aqueous phenol / formaldehyde resin suspension for the production of pressure-sensitive copier paper.

The following examples are intended to explain the invention further.

Example I.

In a stainless steel reactor with a capacity of 100 liters were placed 20 kg of p-chlorophenol, 3.5 kg of 80% para-formaldehyde, 200 g of p-toluenesulfonic acid and 17.5 kg of benzene. The mixture was heated with stirring so that the reaction carried out at 70 to 9O ⁰ C, and the water formed during the reaction was removed as an azeotrope with benzene from the reaction system. After the completion of the reaction, 10.3 kg of 30% sodium hydroxide solution was added to dissolve the reaction product, and after recovering benzene by heating, the solution was diluted with 500 liters of water. Then, 35% hydrochloric acid was added dropwise to the solution to precipitate a polymer, which was then filtered off with a centrifuge. In this way, 20.4 kg of the resin was obtained on a dry basis in the form of a wet cake with a moisture content of about 50%.

2 kg of the sodium salt of a / I-naphthalenesulfonic acid / formaldehyde condensate were added to this moist cake and 0.1 kg of sodium polyoxyethylene stearyl sulfate together with 7 kg of water. The mixture was dispersed into particles with an average by means of a high speed disperser Particle size of 1 μ, which makes about 50 kg of a 40% suspension of the resin received. This suspension had a viscosity of about 30 centipoises easy to process uivd effective as a material for pressure-sensitive copier paper, as the suspension neither parted nor gel when standing for an extended period of time. The results of this example are given as Experiment 1 in Table I below.

Example 2

11.9 kg p-phenylphenol and 9.0 kg p-chlorophenol were with 3.7 kg of para-formaldehyde in the presence of 27.5 kg of benzene and 210 g of p-toluenesulfonic acid implemented similarly as indicated in Example 1. Then 16.8 kg of 33% strength aqueous sodium hydroxide solution were added added and the reaction product dissolved in the heat. Then benzene was distilled off and the solution diluted with 500 liters of water. 35% hydrochloric acid was added dropwise to the solution with stirring. to precipitate the resin, which was then filtered off. In this way, 2 tons, 3 kg of the resin were obtained Dry basis in the form of a moist cake with a moisture content of about 53%.

2.1 kg were added to this moist cake Sodium salt of a β-naphthalene sulfate / formaldehyde condensate, 0.11 kg of sodium polyoxyethylene stearyl sulfate and 5.3 kg of water. The mixture was in worked up in a manner analogous to that described in Example 1, so that a resin suspension was obtained, which, as shown in Experiment 15 (Table I), maintained its stability for 3 months Pressure-sensitive copying paper prepared by applying this aqueous suspension showed excellent properties, particularly in the initial one Color formation and color density compared to a pressure-sensitive copier paper made using a conventional phenol / formaldehyde condensate was produced.

Example 3

28.0 kg of p-phenylphenol. 3.7 kg 80% para-formaldehyde and 0.28 kg of p-toluenesulfonic acid were in 43.2 kg of benzene as described in Example 1 reacted. After completion of the reaction were 19.2 kg of a 33% strength aqueous sodium hydroxide solution was added, and the reaction product was dissolved therein with heating. After the benzene has been separated off by distillation, diluted hydrochloric acid was added dropwise to the solution with stirring and the pH of the solution was adjusted within a range of 4 to 5 to be a Precipitate polymer, which was then filtered and washed with water, so that 55.4 kg of one wet cake received containing 29.5 kg of polymer (dry basis).

3 kg of the sodium salt of a -methyl-β-naphthalenesulfonic acid / formaldehyde condensate were added to this moist cake and 15.4 kg of water. The mixture

tet, so that a 40% aqueous suspension of good quality was obtained, which, as in Experiment No. 10 (Table I) was stable and a pressure-sensitive copier paper excellent in color formation delivered.

Example 4

A 40% aqueous suspension, prepared by mixing the p-chlorophenol obtained in Example 1 / Formaldehyde resin with the sodium salt of /? - naphthalenesulfonic acid / formaldehyde condensate and the sodium salt of polyoxyethylene dodecyl sulfate, was in Weight ratios of 3: 1.1: 1 and I: 3 with a mixed aqueous 40% suspension, the produced

Table I.

by mixing a resin obtained from tert-butylphenol as a starting phenol component similar to that described in Example I, with the sodium salt of jS-naphthalenesulfonic acid / formal -, dehyde condensate and the sodium salt of polyoxyethylene dodecyl sulfate. All of these mixed aqueous Suspensions maintained their stability for 3 months and were good quality materials for use Use for the production of pressure-sensitive copy paper.

Example 5

22 kg of the aqueous suspension of p-chlorophenol / formaldehyde resin of Example I were with a

r> Laboratory spray dryer with an average drying temperature of 55 ° C and an average Feed rate of 4 kg / hour dried. 9.5 kg of the dry powder obtained were further pulverized with a laboratory pulse pulverizer to obtain a fine powder, duS si "« particle size from 2 to 0.105 mm exhibited. 1 part by weight of the resulting product was mixed with 1.5 parts by weight of water so that an aqueous suspension of a resin with a stability equal to that of the original suspension was received.

The following table I explains a comparison of the stability of aqueous suspensions that according to the invention contain dispersants used,

jo and suspensions that do not have a dispersant or a contain previously known dispersants. The dispersion stability of each of the various suspensions was determined by allowing the suspension to stand in a glass cylinder, observing whether

r> the resin separated from the suspension or coagulated.

Experiment no. Phenol component Kc in the condensate resin (G 1 p-chlorophenol 40 2 p-chlorophenol 40 3 p-chlorophenol 30th 4th p-chlorophenol 30th 5 p-chlorophenol 30th 6th p-chlorophenol 30th 7th p-chlorophenol 30th 8th p-phenylphenol 40 9 p-phenylphenol. 30th 10 p-phenylphenol 40 11th p-phenylphenol 40 12th p-phenylphenol 40 13th p-phenylphenol 40 14th p-phenylphenol 30th 15th p-chlorophenol 40 p-phenylphenol 16 p-tert-butylphenol 40

Condensate concentration

Kind and Amount of ). Dispersant on the resin (% By weight 10.0 based 0.5 (A) - 10.0 (B) - 0.5 (C) - 5.0 (B) - 10.0 (D) - 10.0 (E) - 10.0 (F) - (G) - 10.0 none 0.5 (A) - 5.0 (B) - 10.0 (A) - 10.0 (C) - 10.0 (E) - 10.0 (I) - (J) - 10.0 none 0.5 (A) - 10.0 (B) - 0.5 (A) - (H) -

Table I (continued)

12th

Experiment stability

No. B. Notes

2 3 4 5 6 7 8 9 10

12 13 14 15

16

Stable for 3 months

stable for at least 1 month

stable for at least 1 month

Coagulation occurred 24 hours after preparation

Coagulation occurred immediately after manufacture

Coagulation occurred directly after th ^e production

Sedimentation occurred immediately after manufacture

Stable for 3 months

stable for at least 1 month

stable for at least 1 month

Coagulation occurred 2-3 days after manufacture. Coagulation occurred immediately after manufacture Coagulation occurred immediately after manufacture. Sedimentation occurred immediately after manufacture Stable for 3 months

3 months stable according to the invention (example 1)

according to the invention

according to the invention

Comparative example!

Comparative example

Comparative example

control

according to the invention

according to the invention

according to the invention (example 3)

Comparative Example Comparative Example Comparative Example Control

according to the invention (example 2)

according to the invention (example 4)

The dispersants indicated by the letters (A) - ()) in Table I were as follows:

(A) Sodium salt of naphthalenesulfonic acid / formaldehyde condensate

(B) Sodium salt of polyoxyethylene stearyl sulfate

(C) Sodium salt of Λ-methyl-jJ-naphthalenesulfonic acid / formaldehyde condensate

(D) Potassium salt of /? - Naphthalenesulfonic acid / formaldehyde condensate

(E) sodium salt of
Phenolsulfonic acid / formaldehyde condensate

(F) sodium salt of higher alcohol sulfate

(G) Oxyethylene-oxypropylene block copolymer (H) sodium salt of polyoxyethylene dodecyl sulfate

(I) sodium salt of dodecylbenzenesulfonic acid (I) sodium salt of alkylnaphthalenesulfonic acid

Claims (1)

Claims; U Aqueous suspension on the basis of a phenol / formaldehyde resin and a dispersing agent, characterized in that it is a phenol / formaldehyde resin of the formula OH A ₁ where m is an integer from 0 to 10 and Ai, A2 and A3 each represent an alkyl group with 1 to 18 carbon atoms, a cycloalkyl group with 5 to 18 carbon atoms, an aryl or aralkyl group with 6 to 18 carbon atoms or a halogen atom, the molar ratio being from Formaldehyde to phenol compound 0.6 to 1.0: 1.0 is, and as a dispersant, an inorganic salt of a Naphthalene sulfonic acid or alkylnaphthalene sulfone acid / formaldehyde condensate of the general formula